Grinding body

ABSTRACT

A grinding body ( 1 ), which consists of a support material ( 5 ) and an abrasive ( 2 ) adhesively applied thereto, is formed such that the grinding body ( 1 ) has an abrasive-free rim that laterally adjoins the active region of the abrasive ( 2 ).

The present invention relates to a preferably planar grinding body, comprising a carrier material and also an abrasive adhesively applied to the carrier material.

Such grinding bodies are known, for example, as grinding discs or emery cloth, on the market and can be applied to rotary sanders, oscillating sanders, rubber blocks, or the like for processing greatly varying surfaces.

In particular, they are used, for example, in the automobile industry, for the post-processing of flaws in lacquer surfaces. For this purpose, grinding bodies having abrasives of different grains are used, which abrade height differences by a plane-parallel, machine or manually executed movement on the surface. This abrasion process is carried out either dry or with the addition of water-like liquids. The post-processed lacquer surface is subsequently polished to a high gloss using a rotating polishing plate and polishing paste.

The goal of such post-processing is for the lacquered surface to subsequently extend absolutely plane-parallel to the carrier material located underneath and not to differ in any way in gloss and surface structure from the unprocessed, adjoining lacquer surface.

Such a procedure proves to be difficult if the surfaces to be treated are designed as concave. Large-area grinding marks and abrasions in the form of a circular ring surface or in the form of a crescent moon form here by way of the outer edges of the abrasive around the surface to be processed, which is typically quite small in area.

In addition, during the machining of flat surfaces, the formation of crescent-shaped or linear depressions can also occur by way of placement of the grinding body on the surface which is not exactly plane-parallel and the exposed abrasion of the grinding body edges linked thereto, which results in significant post-processing expenditure.

A composite made of a grinding plate and a grinding disc for a rotational sander is known from DE 103 05 189 A1, which is implemented as more elastic in an outer ring-shaped edge region than in the adjoining central region. A high adaptation capability to an uneven contour is thus to be achieved. However, the risk remains that the grinding disc edge will cut in an undesired manner into the lacquer surface in the event of unfavorable placement.

DE 28 05 288 A1 discloses a sanding sheet, which is provided on the rear with a reinforcing layer of a flexible material, which preferably protrudes beyond the edge of the sanding sheet and in this way is to offer protection against grinding in grooves with the sanding sheet edge. Fundamentally, however, groove formation cannot be reliably avoided even with such an arrangement, for example, if the flexible material bends away.

Finally, a grinding body is disclosed in DE 44 40 034 A1, which is provided in the outer edge region with a zone made of an elastic material. This is predominantly used for the purpose of preventing a breakout of grinding grain agglomerates or individual grinding grains from the grinding body edge.

The object of the present invention is to refine a grinding body according to the species in a simple and cost-effective manner such that undesired groove formation can be reliably prevented.

This object is achieved by a grinding body having the features of Patent claim 1.

Advantageous embodiments and refinements are the subject matter of the subclaims.

The abrasive-free edge region of the grinding body according to the invention can be implemented differently.

It is conceivable to implement the carrier material as abrasive-free in this edge region, i.e., only to apply the abrasive in a type of inner area delimited by the edge region, so that this lateral, abrasive-free edge is formed by the superficially-smooth carrier material.

According to a further idea of the invention, it is provided that the abrasive-free edge region is provided by a material which smooths the structure of the abrasive.

In any case, the outer edges of the grinding body, in the case of curved surfaces or in the case of an even placement of the grinding body on the surface to be processed, cannot cut into this surface. The material abrasion is only performed in the case of the novel grinding body by the central region of the grinding body adjoining the edge on the inside.

The smoothing of the abrasive structure can be performed such that the material completely covers the abrasive in the edge region or it fills up the pores between the grains of the abrasive. In both cases, the grinding effect is eliminated in the treated regions.

In the case of a further preferred embodiment of the invention, the material is a mineral material or a polymer material. Plaster can particularly preferably be provided as a mineral material, while a two-component lacquer or a two-component polyester resin can be used as a polymer material. Fundamentally, it is to be ensured in the material selection that the material withstands the heat development generated by friction during the grinding process.

The preferred layer thickness according to the invention of the smoothing material is 30 to 40 μm. Depending on the grain size of the abrasive, it is ensured in the case of such a layer thickness that the individual grains of the abrasive are completely coated or at least the pores between the individual grains are filled up. In this manner, the grinding body loses its grinding effect in the treated edge region.

The material which smooths the structure of the abrasive can be applied, for example, by screen printing, pad printing, spray lacquering, stamping, brush application, immersion, or gluing. Fundamentally, any method is suitable, by which the smoothing material can be applied uniformly to the edge region of the grinding body.

In a preferred embodiment of the present invention, a fabric, a paper, a plastic film, or a carrier plate is used as the carrier material of the grinding body. A film made of polyvinyl chloride (PVC) can particularly preferably be used as a plastic film.

The abrasive preferably adheres to the respective carrier material by way of a binding agent.

On the side of the carrier material facing away from the abrasive, in a preferred embodiment of the invention, a connecting means is applied for connecting the grinding body to a grinding device, for example, an rotary sander or oscillating sander. For this purpose, this can be adhesive, for example, which, as long as the grinding body is not in use, is provided with a cover film. Alternatively, the grinding body can also be applied to a grinding device with the aid of a hook-and-loop closure formed from a hook strip and a loop strip.

The abrasive of the grinding body according to the invention preferably has a grain in a range between 2500 and 7000, particularly preferably a grain of 3000. Grains in this range are particularly suitable for the post-processing of flaws and lacquered surfaces, for example, automobile bodies.

The carrier material of the grinding body according to the invention preferably has a thickness between 30 and 70 μm, particularly preferably a thickness of 50 μm.

The invention will be explained in greater detail hereafter on the basis of an exemplary embodiments and with reference to the appended figures. In the figures:

FIG. 1: shows an exemplary embodiment of a grinding body according to the invention as an emery cloth in a top view;

FIG. 2: shows the grinding body according to FIG. 1 in section area

FIG. 1 and FIG. 2 show a grinding body according to the invention, designated as a whole with 1, as is used, for example, in the automobile industry for post-processing flaws and lacquer surfaces. The grinding body 1 is implemented as an emery cloth having a corrugated edge. Transitions between surfaces of different curvature may advantageously be processed in this way. The grinding body 1 has a top side 10, a bottom side 11, and an edge 100.

The grinding body 1 is composed of multiple layers. A carrier material 5 is arranged in the middle, which consists of a fabric. An abrasive 2 having a 3000 grain is adhesively applied to the carrier material with the aid of a binding agent 4.

An adhesive 6, which is used for the secure attachment of the grinding body 1 to a grinding tool (not shown here), for example, an rotary sander or oscillating sander, is located below the carrier material 5. For protection, the adhesive is initially provided with a cover film 7, which is removed before the attachment of the grinding body 1 to the grinding tool.

A material 3, which smooths the structure of the abrasive, is applied as a cover in the edge region of the grinding body 1. In this case, this is plaster, which is applied by brush application on the edge 100 and on the region directly adjoining the edge 100 on the abrasive-side top side 10 of the grinding body 1.

By way of this plaster application, the abrasive surface structure of the grinding body is covered in the edge region, so that only the central abrasive area is still capable of abrading material. Processing traces and, as a result, post-processing times are thus substantially reduced.

The grinding body 1 is distinguished in particular in that the smoothing material 3 can be applied in a simple and cost-effective manner to already existing grinding bodies 1. 

1. A grinding body (1), consisting of a carrier material (5) and an abrasive (2) adhesively applied thereto, characterized in that the grinding body (1) has an abrasive-free edge, which laterally delimits the active region of the abrasive (2).
 2. The grinding body according to claim 1, characterized in that the abrasive-free edge is formed by an applied material (3), which smooths the structure of the abrasive (2).
 3. The grinding body (1) according to claim 2, characterized in that it is a mineral material or a polymer material (3).
 4. The grinding body (1) according to claim 3, characterized in that plaster is provided as a mineral material (3).
 5. The grinding body (1) according to claim 3, characterized in that a two-component lacquer is provided as a polymer material (3).
 6. The grinding body (1) according to claim 3, characterized in that a two-component polyester resin is provided as a polymer material (3).
 7. The grinding body (1) according to claim 2, characterized in that the material (3) which smooths the structure of the abrasive (2) is applied in a thickness of 30 to 40 μm.
 8. The grinding body (1) according to claim 2, characterized in that the material (3) which smooths the structure of the abrasive (2) is applied by screen printing, pad printing, spray lacquering, stamping, brush application, immersion, or gluing.
 9. The grinding body (1) according to claim 1, characterized in that a fabric, paper, a plastic film, or a carrier plate is used as the carrier material (5).
 10. The grinding body (1) according to claim 1, characterized in that the abrasive (2) adheres to the carrier material (5) by way of a binding agent (4).
 11. The grinding body (1) according to claim 1, characterized in that a connecting means (6) for connecting the grinding body (1) to a grinding device is applied on the side of the carrier material (5) facing away from the abrasive (2).
 12. The grinding body (1) according to claim 1, characterized in that the grain of the abrasive (2) is in a range between 2500 and 7000, preferably at
 3000. 13. The grinding body (1) according to claim 1, characterized in that the carrier material (5) has a thickness between 30 μm and 70 μm, preferably 50 μm. 